The invention is especially contemplated for use in connection with transportation pipes or conduits adapted for installation on the seabed between a stationary or floating offshore platform and an on-shore terminal. However, it is to be understood that the principle of the invention can also be utilized in connection with transportation between seabed installations as well as from the seabed to a platform, and possibly in connection with on-shore systems.
More specifically, the present invention has been developed in connection with offshore production plants for the production of gas and/or oil in which a portion of the gas might be transported ashore via transportation pipes, whilst simultaneously electric power which is generated by another portion of the gas, is transmitted in separate electric cables which preferably run in parallel to the seabed transportation pipeline.
This solution may also serve as a safe back-up system in case of emergency or a shutdown situation offshore. In that case, electrical energy will be transported from an on-shore power station to an offshore platform consumer.
Further, such transmission of electric energy from an on-shore power station which is based on hydro power is also favorable as regards anti-pollution, especially compared with an offshore gas turbine power station based on gas combustion and discharge of CD.sub.2.
In such offshore production plants the availability of hydrocarbon products from the offshore process plants is strongly dependent on the flow efficiency in the export pipeline system. If the temperature in such an export pipeline system is falling below a certain temperature (in the range of 15.degree.C.), crystallization and the development of hydrates would occur, which would bring forth a congestion of the oil/gas mixture which is to be transported through the pipeline system
In order to ensure an efficient flow through the pipelines, the operator must thus have full control of the hydrate and wax deposits, such deposits being avoided or removed by either chemical injection or by heating the pipeline to an appropriate temperature.